Until recently, humans were pretty much restricted to making sounds the way that all the other creatures did--which explains the similar sounds.

The difference between humans and insects seems to be that we develop and expand ideas using sounds. While it is true that animals communicate with each other using noises, the idea of music, which is to say that a bunch of sounds, either in sequence or all at the same time, sounds cool, seems to be ours alone. At least we've done a lot with it. Cicadas have one lick, and they beat it to death.